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Notes: Holographic interferometry using crystals of iron-doped lithium niobate is reported. The interferograms presented are produced via double-exposure Fourier transform holography in heavily doped crystals without applied electric fields. Flow-field visualization is used as an example application area.

Notes: Transepidermal water loss (TEWL), skin surface water loss (SSWL) and water content of the stratum corneum are utilized to assess the hydration effects of moisturizers and soaps. The relationship among these parameters may help differentiating hydration obtained via occlusion or by water-holding in the stratum corneum. Furthermore, skin function (hydration, dehydration, barrier damage) can be studied comparing the data obtained with these techniques. In this study, the effects of glycerol, petrolatum, soaps and commercial moisturizers on the skin are investigated and discussed.

Notes: Stratum corneum moisturization was measured by two instruments simultaneously on the same subjects at different body sites. One instrument is based on the 1 GHz focused mirowave dielectric measurement; the other instrument measures impedance at 16 Hz.A linear relationship r = 0.86 was observed between the measurements by the two above-mentioned instruments. The 1 GHz focused microwave measurement is more accurate in measuring water concentration in the stratum corneum, especially in the upper layers relevant to “moisturization”; it is, however, an expensive research instrument. The low frequency impedance measurement involves a much simpler, cheaper and portable instrument which can be used routinely to evaluate ‘moisturization’ for the purpose of skin classification under field conditions.Comparaison de divers appareils de mesure de I'hydratation de la couche cornee〈section xml:id="abs1-2"〉〈title type="main"〉ésuméL'hydratation de la couche cornée a été mesurée simultanément par deux appareils sur plusieurs sites de mêmes sujets: le front, la face et les membres. Un appareil est basé sur la mesure par micro ondes, I'autre mesure I'impédance à 16 Hz.On observe une relation linéaire, r= 0.86, entre les mesures effectuées par les deux appareils ci-dessus. L'appareil à micro ondes est plus précis pour la mesure de la concentration en eau de la couche cornée et plus spécialement dans les couches supérieures qui sont importantes pour I'hydratation, mais cet appareil est onéreux. La mesure des impédances à basse fréquence utilisé un appareil portable, simple et bon marché qui peut être utilisé en routine pour évaluer I'hydratation dans le but de classer des types de peaux sur le terrain.II n'est pas toujours possible de comparer des appareils diffeérents sur les mêmes personnes et dans le même temps et il est encore plus difficile d'obtenir des donneées sur un nombre de personnes de type diffeérent. Nous suggeérons d'utiliser à I'avenir une meéthode de comparaison diffeérente basée sur I'application d'un traitement standard bien défini, qui pourrait par example consister en I'application pendant une heure d'une solution à 2% de glycérine sur I'avant bras, avant la mesure.Ces données, avec la connaissance de la distribution des valeur du prétraitement pour les divers appareils, permettraient également la comparaison et la validation des différentes méthodes.

Notes: Reactivity to repeated daily sodium lauryl sulfate (SLS) applications and patch test reactivity to SLS was studied in 23 females. Skin changes were quantified by transepidermal water loss (TEWL), dielectric water content (DEWC), laser Doppler velocimetry (LDV) and visual scaring DS). Dermatologic histories (HS) and susceptibility to sunburn (ST) were obtained and clinical skin dryness evaluated (DS). Great interindividual variation occurred in the degrees of changes in (he biophysical parameters measured; the variation was most apparent in TEWL. The subjects with HS I or more developed greatest TEWL increase after open SLS applications (p 〈 0.05). DS showed poor correlation with SLS reactivity and only minor DEWC alterations were seen. ST showed some non-significant correlation with erythema reactivity in the patch test.

Notes: Repeated, daily, open sodium lauryl sulfate (SLS) applications caused slight alteration in transepidermal water loss (TEWL) and dielectric water content (DEWC) in males and females. No erythema developed. Inter-individual variation in skin reactivity was demonstrated; sex-related patterns in reactivity open cumulative irritant exposure did not exist. In patch testing with 0.5 and 1% SLS. reflecting acute irritation capacity. the reaction pattern, assessed by TEWL. DEWC, laser Doppler velocimetry (LDV) and visual scoring(VS). differed from that induced by open. cumulative: SLS irritation. Again. inter-individual variation in the reactivity was demonstrated: significant sex-related differences did not develop Individual reactivity showed considerable variation in acute and cumulative irritant response and was greater than the sex-related variation. We did not identify responses demonstrating that women have delicate (easily irritated) skin, nor that males have “tougher” skin than females.

Notes: The variation in human skin response to sodium lauryl sulfate (SLS) was determined, with patch and open applications. Reactions in different subjects and in multiple simultaneous patch tests were compared. Skin responses were assessed with visual scoring (VS), laser Doppler velocimetry (LDV) and transepidermal water loss (TEWL). Previous open, unpatched SLS exposure decreased patch lest reactivity to 1% SLS assessed with VS (p〈0.05) or LDV (p〈0.05). Corresponding TEWL alteration was inconstant. Variation in reactivity at different test sites in multiple simultaneous tests was considerable, though less than the variation at different test times (p〈0.05). Inter-subject variation in test reactivity was greater than the variation between different test times or adjacent test sites. Repeated open applications and the subclinical dermatitis appear to have produced a hyporeactive state. The results suggest that non-specific skin inflammation is elicited by multiple factors, e.g., stratum corneum integrity and vascular reactivity. Their balance determines the ensuing reactions. The induced hyporeactivity may be one of many causes of false negative diagnostic patch tests.